The present invention relates to a method for generating a predetermined or predeterminable receiving characteristic of a digital hearing aid comprising at least two microphones, the outputs of which are subjected to analog-digital conversion and the digitized signals are superposed in additive manner after at least one of them has been subjected to a prescribed or adjustable time delay, the analog-digital conversion of the at least one time-delayed signal being implemented by oversampling.
The invention also relates to a digital hearing aid comprising at least two microphones, each followed by an analog-digital converter. At least one converter is operationally connected, by a delay device, to an additive superposition unit and at least the analog-digital converter acting through the delay device on the superposition unit is designed as an oversampling analog-digital converter.
The so-called xe2x80x9cdelay-and-addxe2x80x9d method is known to generate predetermined or predeterminable receiving characteristics, particularly for digital hearing aids comprising at least two microphones.
Such a procedure is known from the German patent document 198 14 180, wherein the signal delay is implemented immediately after the sigma/delta conversion, i.e., the delay device immediately follows the sigma/delta converter. Oversampling takes place during sigma/delta conversion. Such a procedure offers the advantage that the time delay can be adjusted in fine steps.
An objective of the present invention is a procedure of the abovementioned sort wherein the time delay and signal matching can be optimally combined. In accordance with the present invention, following down-sampling, the oversampled converted digital signal is both time-delayed and level-matched. Alternatively, the delay device of the hearing aid is designed as a down-sampled filter element at which level-matching of the signals fed to the superposition unit also shall take place.